Zombie process using CPU

Ike Panhc ike.pan at canonical.com
Tue Apr 20 06:57:47 UTC 2010


Sounds like kill its parent is a bad idea. I remember I have made
some of the zombie process before, but not anymore after I force the
parent to ignore SIGCHLD before fork.

I believe it can be fixed by modifying something in the application
not in the kernel.

John Tapsell wrote:
> On 20 April 2010 14:27, Ike Panhc <ike.pan at canonical.com> wrote:
>> Hi,
>> IIRC zombie process is waiting for his parent process to end him.
>> If I see an zombie process, I will use "pstree" to find his parent
>> process and see what I can do. Maybe kill the parent process.
> Ah I forgot to mention - I did indeed kill its parent and it became
> re-parented to init.
> So we had a zombie process whose parent is init.
> John
>> Hope its helpful.
>> John Tapsell wrote:
>>> Hi,
>>>   After a program (vuze) crashed I ended up in the situation of having
>>> a process, java, using 100% CPU of a core while also being a zombie.
>>>   Looking in /proc/<pid>/task  I saw two pids - the main task and a
>>> subtask.  The main task (cat /proc/<pid>/task/<pid>/status ) was
>>> indeed a zombie, but the subtask was still running and using CPU.
>>>   I could not find any way to kill this process. kill -9  on the <pid>
>>>  and on the pid on the subtask did nothing.  In the end I had to
>>> reboot.
>>>   is this situation supposed to be possible?  How do I kill a subtask?
>>> John

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